Integrated circuit chips may be carried in chip carriers such as plastic chip carriers with leads, these devices being commercially available. For mounting a chip carrier on a circuit board or the like, a chip carrier socket is used, with various designs of these sockets being commercially available.
One type of chip carrier socket which is currently available to the market is of the J-lead type. Such a chip carrier socket is a carrier structure defining a recess with a closed bottom for carrying the chip. A plurality of contact members are carried by the socket about the chip for entering into electrical contact with separate terminals on the periphery of the chip. The contact members of the socket then extend to one side thereof, which side is secured to a circuit board with the contacts being in electrical contact with conductors carried on the circuit board.
Chip carrier sockets may be mounted on a circuit board with through-board mounting with wave solder attachment. Alternatively, the sockets may be surface mounted by the use of a solder layer applied to the board and then heated so that the solder adheres the chip carrier socket to the board.
The J-lead type chip carrier socket has contacts which project inwardly toward their ends along the side of the socket which is attached to the circuit board. While such a configuration is space saving, it has the disadvantage that there is no way to inspect the connections of the contacts to the board or to repair faulty connections.
Another commercial design of chip carrier socket is the "gull-wing" type. This socket has similarities to the J-lead style, except that the contacts which connect the periphery of the chip to the circuit board have ends that extend outwardly rather than inwardly along the socket side which faces the board. This provides a socket system where the individual connections between the contacts and the board may be inspected and repaired if necessary. However, such a socket occupies more "real estate" on the board than the J-lead socket, and the outwardly projecting prongs of the terminals are subject to bending or other damage in handling.
While the gull-wing socket can be used with infrared soldering processes, the J-lead socket cannot, providing an additional disadvantage of that design.
In accordance with this invention, a new design of chip carrier socket is provided which has significant advantages over older designs. First, while the prongs of the contact members which adhere to the board can project inwardly for protection, they are still visible for inspection and repair of their seal to the board, and are usable with infrared soldering type processes, vapor phase bonding processes, and other surface mounting techniques.
The chip carrier socket of this invention may have a lower height than prior art designs, while the contact between the chip and the carrier socket may still be preloaded because of the novel design of terminal used herein. The chip carrier socket of this invention may use the same mounting pattern as an accompanying chip, and is fully compatible with all surface mount processing techniques. Also, it is susceptible for robotic assembly and adhesive bonding if that is desired, and may be used with optional polarizing pegs, and visual and mechanical polarization.